1. Field of the Invention
The present invention relates to the use of selected beta-nitroalkenes as cetane number boosters for diesel fuel.
2. Description of the Prior Art
It is known to add small amounts of certain chemicals to diesel fuel to decrease ignition delay and as a result, increase the cetane number of the fuel. These cetane boosters include nitro-parrafin compounds such as nitroethane and nitropentane and alkyl nitrite compounds such as isopropyl nitrite, butyl nitrite and ethyl nitrite (See U.S. Pat. No. 1,820,983); nitric acid, sodium nitrate, or oxides of nitrogen, or mixtures of nitric acid and sulfuric acid (See U.S. Pat. No. 2,240,558); gem dinitro alkanes and cycloalkanes (See U.S. Pat. Nos. 2,387,279; 2,387,403; and 2,560,904); alkyl nitrates such as amyl nitrates (See U.S. Pat. No. 2,857,253); trinitroalkanes such as 2,2,3-trinitrobutane (See U.S. Pat. No. 3,000,971); and gem dinitroalkanoates such as methyl 4,4-dinitropentanoate (See U.S. Pat. No. 3,380,815). U.S. Pat. No. 4,073,623 teaches incorporating into diesel fuel a mixture of an iron salt of an aromatic nitro acid and a nitroaliphatic compound having one to four carbon atoms (cited compounds include nitromethane, nitroethane, nitropropanes and nitrobutanes) in order to reduce air pollutants to lower hard carbon deposits in diesel engines and to prevent or retard slime deposits in the diesel fuel.
With the continued increase in demand for diesel fuel in both passenger cars and trucks and the economic constraints on the quality of available diesel fuel, there is still a need for new and more economical cetane boosters. Accordingly, one object of the present invention is to provide new and more economical cetane boosters.
Another object is to offer a method to improve good grades of diesel fuel and also increase the range of usefulness by raising the cetane number of lower grade fuels to a point where they can be used.